Improvement in combined spirit-levels



, CAHooN, 1r.

Spirit Level.

Patented May 2o. 1862.

; l74551zeazsusay. Madan N. PETERS. wwumomphu wmvngmm ac.

. drawings.

UNITED STATES PATENT OEEICE.

ALviN `oAriooN, JE., OE HAEwIcrr, MAssAoi-IUsETTs.A

IMPROVEMENT IN COMBINED SPIRIT-LEVELS.

Specification forming part of `Letters Patent No. 35,298, dated May 20, 1862.

To all whom it may concern.`

Be it known thatI, ALVIN CAHOON, Jr., of I-Iarwich, in the county of Barnstable and State ot Massachusetts, have invented a new and useful instrumentfor determining the trim of vessels,which I denominate a Pleiometer; and I do hereby declare that the folbestsuited to rapid motion, and which, varying with different vessels, it is important to ascertain by experiment and to conform to as nearly as possible. This is usually called the sailing trim or the best sailing trim of the vessel. The means generally employed to attain these objects have consisted in simply inspecting the position of the vessel in the water from the exterior, which is not only very deficient in accuracy, but occupies much time and is difficult of attainment. My instrument shows at a glance, Or by a simple adjustment, the exact fore-and-aft trim of the vessel', as also whether it is onV an even keel, and by its means the cargo can be readily stowed to produce any trim desired.

The nature of my invention consists in an improved instrument consisting ot' two horizontal spirit-levels at right angles one to the other,and one of them4 rendered adjustable in the vertical plane by means of a micrometer screw and scale or equivalent device, for the purpose of determining the position of a vessel in the water, both the f-heel and fore-andfaft trim,7 and thereby indicate the proper disposition of` the cargo for obtaining an even keel and the best sailing trim.

To enable others skilled in the art to which this invention relates to make and use the instrument, I will proceed to describe its construction and operation by the aid of the A is a bar of wood carrying a spirit-level, a, attached lin the ordinary manner.

B is a similar bar hinged to A at one end, as represented,

C is a graduated scale attached to IB, and

D is a pointer or vernienscale attached to A to indicate the angle between A and B.

E is a screw threaded into A, and so attached to B by means of a collar and nut, e, as represented, that while it is free to turn on its axis and to slide laterally in B to a small extent to compensate for the variation in the angle B it is compelled to move either to or from A as E is turned in the corresponding direction without lost motion. A coiled spring to torce A and B apart, with a screw to `compress it and draw them together, or any lother equivalent arrangement, may be used in place of the screw E, it' desired. The bar B is widened at or near the center, as represented, and another spirit level, I, placed therein at right angles to the level a.

In operating my invention a place is provided'on the cabin-iioor or at any convenient part of the vessel at right angles to the plane of the masts, on which the ploiometer is placed, with its length ranging fore and aft. Then the vessel is trimmed to her best sailing condition, the part A is brought to a perfect level by means of the screw E, an`d the angle indicated on the scale C carefully noted. New by placing the ploiometer in the same position and adjusted to the .same angle when stowing cargo the level d will indicate her proper trim fore and aft, while the level I tells when she is on an even keel, and 4it is only necessary to stow the cargo in such a manner as to bring the bubble of each to its respective center point to produce the desired condition. j Y

I do not claim, broadly, the employment of two spirit-levels at right angles one to the other, as such is well known in the ordinary spirit plumb and level. Neither do I claim rendering a spirit-level adjustable at small angles, as is shown in the rejected application of Henry Aston, 1856; but

Vhat I do claim as my invention, and desire to secure by Letters Patent, is-

The instrument herein described, consist ing of two horizontal spirit-levels at right angles one to the other, and one of them rendered adjustable in the vertical plane for the purpose of determining the trim ofa vessel, substantially as herein described.

In testimony whereof I have here unto set my hand in the presence of two subscribing witnesses.

Witnesses: ALVIN CAHOON, JR.

O BED BROOKS, GEO. H. SNOWE 

